im new and need help!
09-09-2007 | 02:53 PM
#1
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im new and need help!
hello...im new to this site
i have one question about a set of heads...im getting ready to rebuild the motor in my 94 gmc sierra 5.7L. i heard a set of 305 heads would change the compression around on the motor and add a lil more torque...and aluminum vortec 2.02 heads are a really good flowing...so which do you recommend? thank you
i have one question about a set of heads...im getting ready to rebuild the motor in my 94 gmc sierra 5.7L. i heard a set of 305 heads would change the compression around on the motor and add a lil more torque...and aluminum vortec 2.02 heads are a really good flowing...so which do you recommend? thank you
09-09-2007 | 03:55 PM
#2
I have a '92 GMC Suburban with the same throttle body injection engine. If I were going to rebuild the engine and put better heads on it, I would install something like the Patriot SBC 195 cc intake runner heads http://www.patriot-performance.com/w...05238&DID=1225 because they will outflow the stock or the Vortec heads by a bunch.
If you buy the Vortec or the 305 heads you will need to do a good valve job with maybe new guides and maybe new valves too (depends on the heads). You will need to replace the valve seals and should replace the springs. The GM Vortec heads were set up for a multi-port intake manifold (rather than the throttle body like you have) and I think that they will fit your engine, but some modification may be required. The 305 heads are higher compression as I recall, but if that's all you want to do, get your heads rebuilt and milled a few thousandths.
Most of us are on a budget, but I think that buying a good set of heads would be the best money you could spend if you want to really improve the performance of your truck. You need to think about your long term plans for the truck, your budget, etc. and work toward your goals.
Steve
If you buy the Vortec or the 305 heads you will need to do a good valve job with maybe new guides and maybe new valves too (depends on the heads). You will need to replace the valve seals and should replace the springs. The GM Vortec heads were set up for a multi-port intake manifold (rather than the throttle body like you have) and I think that they will fit your engine, but some modification may be required. The 305 heads are higher compression as I recall, but if that's all you want to do, get your heads rebuilt and milled a few thousandths.
Most of us are on a budget, but I think that buying a good set of heads would be the best money you could spend if you want to really improve the performance of your truck. You need to think about your long term plans for the truck, your budget, etc. and work toward your goals.
Steve
09-10-2007 | 02:31 PM
#3
Patriot heads are nice but with a TBI unit only flowing 550cfm max without mods...you really need to look into a good cast vortec head like the '906' and then do the ultimate TBI mods combined with a great cam. A normal cam won't go above .520 lift and the Patriots start to flow around .500....but for .400 and under is where you need to look for a street engine. Low lift numbers help torque/etc. IMO, this would be a great setup for a TBI engine and it really is a great setup....I've built it for some people and people love it....here is the combo:
350 with 9.5:1 compression
Comp 212/218 cam or a 206/212 for more low end depending on what you want
Vortec '906' heads, springs to match the cam
Edlebrock Air gap or GM vortec TBI manifold....with the air gap...you will need a carb to TBI spacer....only $40 bucks.
Ultimate TBI mods....adj. fuel pressure regulator, flow matched injectors, injector spacer and polished bores with rolled edges.....
Also, if you haven't done it already...get some headers like Hedman and a K&N open air filter assembly to help the engine breathe and exhale.
A custom tune will also be needed....look at PCMforless or PM me and I'll get you a few other places to look at.
350 with 9.5:1 compression
Comp 212/218 cam or a 206/212 for more low end depending on what you want
Vortec '906' heads, springs to match the cam
Edlebrock Air gap or GM vortec TBI manifold....with the air gap...you will need a carb to TBI spacer....only $40 bucks.
Ultimate TBI mods....adj. fuel pressure regulator, flow matched injectors, injector spacer and polished bores with rolled edges.....
Also, if you haven't done it already...get some headers like Hedman and a K&N open air filter assembly to help the engine breathe and exhale.
A custom tune will also be needed....look at PCMforless or PM me and I'll get you a few other places to look at.
